Predictors of medication nonadherence among patients with diabetes in Medicare Part D programs: A retrospective cohort study

Objectives: This study examined the prevalence of nonadherence with oral hypoglycemic agents, antihypertensive drugs (angiotensin-converting enzyme inhibitors [ACEIs] and angiotensin II receptor blockers [ARBs]), and statin medications among Medicare Part D enrollees with diabetes and analyzed the potential demographic and clinical factors that predict medication nonadherence.Methods: This was a retrospective cohort study of Medicare Part D enrollees with diabetes from 6 states (Alabama, California, Florida, Mississippi, New York, and Ohio). Adherence was calculated as the proportion of days covered (PDC; number of days with medication on hand/number of days in the specified time interval). A PDC was derived for each of the 3 categories of medications for patients who had at least 1 claim for the same class of medication. A comorbidity measure was created for each beneficiary using the Deyoadapted Charlson Comorbidity Index (CCI). Associations between nonadherence and patient characteristics including age, sex, race/ethnicity, and Deyo-adapted CCI were examined. Logistic regression models were constructed to identify predictors of nonadherence.Results: The study included 1,888,682 patients with diabetes. The mean (SD) age was 71.6 (11.6) years, and 59.5% (1,123,220/1,888,682) were female. A total of 66.4% (1,254,538/1,888,682) were white, 16.3% (308,158/1,888,682) were black, and 7.8% (147,498/1,888,682) were Hispanic. Estimated rates of non-adherence for oral hypoglycemic agents, ACEIs/ARBs, and statins were 35.1% (386,666/1,101,533), 41.8% (449,561/1,075,285), and 46.4% (447,106/962,877), respectively. In unadjusted analyses, patients aged <65 years, women, black or Hispanic patients, and patients with higher Deyo-adapted CCI were more likely to be nonadherent to all 3 classes of medications. The results were consistent in multivariate analyses, and all results were statistically significant at P < 0.001.Conclusions: In this study of Medicare Part D enrollees with diabetes, patients aged <65 years, women, black or Hispanic patients, and those with higher comorbidity scores were more likely to be nonadherent to medications. Interventions should be developed to improve medication adherence among these subgroups so that patients can achieve the full benefits of prescribed pharmacologic therapies.     

Changes in preventable hospitalization patterns among the adults: a small area analysis of US states

The study examines the variation and changes in preventable hospitalization (PH) rates across small areas over 1995-2005 in 5 US states for adults (aged 18-64 years). Using hospital discharge data from the Agency for Healthcare Research and Quality and contextual data from Health Resources and Services Administration, the study examines the role of managed care, primary care physician supply, and sociodemographic factors on adult PH rates. A stronger influence of minority and uninsured status, weaker contributions of managed care enrollment in the commercial as well as in the Medicaid markets, and weaker contributions of primary care density may have caused slower than expected reduction in adult PH rates.     

High-risk Diabetic Patients in Medicare Part D Programs: Are They Getting the Recommended ACEI/ARB Therapy?

BACKGROUND

Diabetes patients with hypertension and/or renal disease are at an increased risk of cardiovascular morbidity and mortality. Clinical evidence suggests that the use of ACEI/ARB for these patients improves patient outcomes.

OBJECTIVE

To describe ACEI/ARB utilization among high-risk patients with diabetes and to identify patient characteristics that predict suboptimal utilization of ACEI/ARB.

DESIGN

A retrospective cohort study.

PATIENTS

Diabetic patients with coexisting hypertension and/or renal disease with continuous Medicare coverage from October 1, 2005 through June 30, 2006 in six states (Alabama, California, Florida, Mississippi, New York, and Ohio).

INTERVENTIONS AND MEASUREMENTS

Any ACEI/ARB use during the first 6 months of 2006.

RESULTS

A total of 1,250,466 Medicare Part D enrollees met our inclusion criteria. ACEI/ARB utilization rates were 63%, 58.3%, and 43.1% among diabetic patients with hypertension and renal disease, hypertension without renal disease, and renal involvement without hypertension, respectively. After adjusting for all other characteristics studied, patients in the hypertension only (OR 0.83; 95% CI: 0.82–0.84) and renal disease only (OR: 0.48; 95% CI: 0.46–0.50) risk groups were less likely to use ACEI/ARB compared to diabetes patients with both hypertension and renal disease. Several demographics, including male gender, age older than 65, and white race, were all predictors of suboptimal ACEI/ARB use. Results from state-specific analyses are consistent with those for all six states.

CONCLUSION

In this cohort, less than 60% of high-risk patients with diabetes were receiving the recommended ACEI/ARB therapy. Several patient demographic and clinical characteristics are strongly associated with suboptimal ACEI/ARB use.